Recently I've found this paper : http://www.mathpages.com/home/kmath280/kmath280.htm, dealing with the Newtonian precession . It inspired me for making the following simulation , in which we have 2 stars each having Msun and are orbiting at 0.1 Au . There's also a planet which has eccentricity 0.5 and is at 5AU . The period of the planet is about 2 years . After about 215 revolutions the aphelion has precessed over 360° as can be seen in this animation . Quite fast ! The driving force for the precession is here the torque the planet experiences by the rotating binary .

If , in the highy exceptional case, the planet starts in a polar orbit we meet an old friend : Kozai . The planet starts precessing in the polar orbit but gets disturbed very slowly first , then gets excited and tilts away from his polar orbit to finally get an inclination of about 66° , which is overshoot . The planet then tends to the original polar orbit and the cycle starts over again .

The precession itself causes no instability . I've run a sim for 20 periods of precession and find no signs of instability , even with a two planet system . I can post the results . However , if orbits are crossing the planets may influence each other . Planets which are further away precess slower than those which are closer

Interesting - is precession the only effect the binary has on the planets? (I'm presuming the orbits of the planets were coplanar?) I would have thought that the planets get into some kind of resonance whereby they never come close to eachother despite the crossing orbits... do you see that happening at all?

Interesting - is precession the only effect the binary has on the planets? (I'm presuming the orbits of the planets were coplanar?) I would have thought that the planets get into some kind of resonance whereby they never come close to eachother despite the crossing orbits... do you see that happening at all?

And also, does this precession happen at all if the planet's orbit a solo star instead of a binary? i.e. is the rate of precession already there but accelerated by the binary?

A single star with one planet does not show precession . Adding another planet will give precession of both planets . This precession is small , as is the case in our solar system .

If we start with a binary all the planets will experience a strong precession . This is what I tried to show in the animations . The reason of this precession is that the planets are attracted by two strong central stars which rotate around a common barycenter .

Question for Tony : I tried to input the following system ( HW Virginis ) ( data available from exoplanets links)

M1=0.485Msun, M2=0.152 Msun at 2037500 km , ecc=0 c : 8.47Mj, 3.62Au , ecc 0.31 orbiting M1 b : 19.23Mj, 5.30 Au, ecc 0.46? , orbiting M1. I think I once again have the "." problem when inputting because the planets fly away just after starting . I first created M2 around M1 , no problem , then created c and b around M1. Is it possible to give the system a try ?

You can't have c and b orbit M1 without also orbiting M2, as M2 is only 2 million km away from M1. So you have to check the "barycenter" option under the "Reference Object" in the Create Objects interface when creating b and c.

I tried it and got it to work, but this system doesn't look very stable. With b & c at 3.62 & 5.3 AU, and high eccentricities, their orbits intersect each other.